LTE_RLC_协议解读.pptVIP

LTE RLC Sub Layer ARQ procedures – Polling Retransmission Polling is to trigger STATUS reporting at the peer AM RLC entity STATUS PDUs is to provide positive and/or negative acknowledgements of RLC PDUs * 5.1 Data transfer procedures 5.1.1 TM data transfer 5.1.2 UM data transfer 5.1.3 AM data transfer 5.2 ARQ procedures 5.2.1 Retransmission 5.2.2 Polling 5.2.3 Status reporting 5.3 SDU discard procedures 5.4 Re-establishment procedure 5.5 Error Handling RLC procedures Spec 36.322 5.xx BCCH, PCCH and DL/UL CCCH TM发送实体 ??不对RLC SDU进行串接，分段 ??没有RLC头 ??对RLC SDU不做任何改动，发送到下层协议实体（MAC层） 3. TM接收实体 ??不做任何修改地递交RLC SDU到上层协议实体（PDCP层） ??向上层递交TMD PDUs（也就是RLC SDU） TM RLC entity 4.2.1.2.2 Transmitting UM RLC entity When a transmitting UM RLC entity forms UMD PDUs from RLC SDUs, it shall: - segment and/or concatenate the RLC SDUs so that the UMD PDUs fit within the total size of RLC PDU(s) indicated by lower layer at the particular transmission opportunity notified by lower layer; - include relevant RLC headers in the UMD PDU. 4.2.1.2.3 Receiving UM RLC entity When a receiving UM RLC entity receives UMD PDUs, it shall: - detect whether or not the UMD PDUs have been received in duplication, and discard duplicated UMD PDUs; - reorder the UMD PDUs if they are received out of sequence; - detect the loss of UMD PDUs at lower layers and avoid excessive reordering delays; - reassemble RLC SDUs from the reordered UMD PDUs (not accounting for RLC PDUs for which losses have been detected) and deliver the RLC SDUs to upper layer in ascending order of the RLC SN; - discard received UMD PDUs that cannot be re-assembled into a RLC SDU due to loss at lower layers of an UMD PDU which belonged to the particular RLC SDU. UM实体配置用于从以下逻辑信道传送/接收RLC PDU：DL/UL DTCH. UM传输实体 根据MAC层的指示期待的RLC PDU大小进行分段或者串接RLC SDU 具有相应的RLC头部 UM接收实体 检测重复的UMD PDU，并丢弃 重新排列失序的UMD PDU 能够检测出UMD PDU在MAC层已经丢失，从而避免延长重排序的时间 将已经排序的UMD PDU 重组成RLC SDU，并递交给上层 如果发现属于某一个特定的RLC SDU的UMD PDU丢失，则把其他属于这个RLC SDU的PDU丢弃 UM RLC en